Elastic fluid turbine



April 3, 1934. G. STANDERWICK ELASTIC FLUID TURBINE Filed Dec. 1, 1932 InventoP Reginald G. Standevwick Patented Apr. 3, 1934 UNITED STATES ELASTIC FLUID TURBINE Reginald G. Standerwick, Marblehead, Mass, as

signor to General Electric Company,- a corporation of New York Application December 1, 1932, Serial No. 645,263

4 Claims.

The present invention relates to elastic fluid turbines wherein elastic fluid is extracted from an intermediate stage for industrial purposes and wherein the exhaust from the turbine is used for industrial purposes. Such a turbine may be termed a back pressure extraction turbine.

In such a machine, it is desirable to regulate the turbine in terms of load, 1. e., speed, and also in terms of extraction pressure and of back pressure or exhaust pressure so that the machine will carry the desired load and at the same time maintain substantially constant pressure in the extraction stage and in the exhaust conduit. When a turbine of this type does not have its speed fixed by some external means, such as, for example, by an alternating current generator which it drives and which is tied in in parallel with other alternating current generators, the regulation ofiers special difficulties because the machine cannot be regulated in terms of load and also in terms of extraction pressure and of back pressure. This situation is met with, for example, when a back pressure extraction turbine is utilized to drive a direct current generator.

The object of my invention is to provide improved regulating means for an elastic fluid turbine of the above referred to type, and for a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims appended thereto.

In the drawing, the figure is a more or less diagrammatic view, partly in section, of a back pressure extraction turbine provided with regulating mechanism embodying my invention.

Referring to the drawing, 1 indicates an elastic fluid turbine having a shaft 2 on which are arranged bucket wheels 3. Elastic fluid is admitted to the turbine by means of a conduit 5 in which is located a regulating valve means 6. The exhaust conduit is indicated at '7. It supplies exhaust elastic fluid for industrial purposes which means that there is a variable demand on it and that the exhaust pressure must be maintained substantially constant. Connected to an intermediate stage 8 of the turbine is an extraction conduit 9 through which elastic fluid of a pressure higher than that of the exhaust pressure is supplied for industrial purposes. Here again, the demand for elastic fluid is a variable one and the extraction pressure must be maintained substantially constant. The flow of elastic fluid from extraction stage 8 to the next lower stage is controlled by a suitable stage valve, here indicated diagrammatically as a simple over-flow valve 10. In practice, a valve of the ring type such as that shown in patent to Norton No. 1,091,078 is generally used.

Connected to valve means 6 is a speed governor 11 which is driven from the turbine shaft and regulates the admission of elastic fluid to the turbine in the terms of speed, i. e., load on the turbine. Connected to stage valve means 10 is a pressure responsive device 11 which in turn is connected by a pipe 12 to the exhaust conduit of the turbine. The pressure responsive device 11 is illustrated as being in the form of a casing in which is located a corrugated diaphragm 13 which is connected to valve means 10 by a stem 14 and pivoted lever 15. This arrangement is shown only by way of example. Any suitable pressure responsive device and connection to the extraction stage valve means may be utilized. With this arrangement, valve means 10 is positioned in accordance with the exhaust pressure of the turbine, the valve means being closed somewhat when the exhaust pressure increases and opened somewhat when the exhaust pressure decreases. By this means, the exhaust pressure is maintained substantially constant.

The pressure in extraction stage 8 and extraction conduit 9 is maintained substantially constant by admitting to it high pressure elastic fluid controlled by a suitable reducing valve positioned in accordance with the pressure in the extraction stage. To this end, there is connected to extraction conduit 9 a conduit 16 in which is located reducing valve 1'7. Reducing valve 17 has its stem connected by a lever 18 to a suitable pressure responsive device 19 which is connected to conduit 16 beyond reducing valve 17 as regards the flow of elastic fluid through conduit 16 by a pipe connection 19a. Conduit 16 may lead from any suitable high pressure elastic fluid supply. With this arrangement, when the pressure in the extraction stage decreases, pressure responsive device 19 will open reducing valve 17 further to admit more elastic fluid to extraction conduit 9, thereby increasing the pressure, while when the pressure decreases in extraction conduit 9, pressure responsive device 19 closes reducing valve 17 somewhat, thereby decreasing the pressure in the extraction conduit 9. By this arrangement the pressure in extraction conduit 9 and extraction stage 8 is maintained substantially constant. Connected to extraction conduit 9 is a pressure relief valve 20 which may be set for a pressure a suitable amount higher than the extraction pressure.

Connecting extraction conduit 9 to extraction conduit '7 is a conduit 21 in which is located a pressure reducing valve 22 having its stem conheated by a lever 23 to a pressure responsive device 24 which is connected to conduit 21 beyond valve 22 as regards the direction of flow of elastic fluid through conduit 21 by a pipe connection 24a. Pressure responsive device 24 is set to open reducing valve 22 when the pressure in exhaust conduit 7 decreases to a ore-determined low value. In back pressure conduit 7 is arranged a pressure relief valve 25 of suitable construction which is set for a pressure a predetermined amount higher than the normal back pressure in conduit '7.- Also in back pressure conduit 7 is a waste valve 26 having its stem connected to a lever 27 which in turn is connected to a pressure responsive device 28 connected by a pipe 29 to extraction conduit 9. With this arrangement, waste valve 26 is controlled by the pressure in extraction conduit 9, being opened when the pressure in extraction conduit 9 increases beyond a predetermined low value. These several pressure responsive devices and relief valves are shown diagrammatically. It will be understood that suitable constructions may be utilized having adjusting means so that they may be set for the desired values.

The operation is as follows:

Assume that the turbine is running, carrying a certain load, and that with the valve means 10 and 17 in the positions shown, both being opened somewhat, the desired pressures obtain in extraction conduit 9 and exhaust conduit 7. Pressure responsive device 28 is set for a pressure some what higher than the normal pressure in extraction conduit 9 so that waste valve 26 is normally held closed. Pressure responsive device 24 is set for a pressure somewhat lower than the normal pressure in exhaust conduit 7 so that valve 22 is maintained normally closed. If the load on the turbine increases or decreases, speed governor 11 will open farther or close somewhat valve means 6, thus increasing or decreasing the amount of elastic fluid supplied to the turbine to take care of the change in load. This will tend to increase or decrease the pressure in extraction stage 8 with the result that pressure responsive device 19 will move reducing valve 17 toward closed or open position, thereby decreasing or increasing the flow of elastic fluid past valve 17 to extraction conduit 9 to bring the pressure back to normal value. If the increased or decreased flow effects an increase or decrease of pressure in exhaust conduit 7, pressure responsive device 11 will adjust valve means 10 to bring the pressure in the exhaust conduit to normal value.

As the demand for extraction elastic fluid from extraction stage 8 increases and decreases, reducing valve 17 is actuated by pressure responsive device 19 to admit more or less elastic fluid to extraction conduit 9, thus taking care of the fluctuating demand for elastic fluid.

When the demand for exhaust elastic fluid increases and decreases, pressure responsive device 11 actuates valve means 10 to eflect the flow of a greater or lesser amount of elastic fluid from extraction stage 8 to the exhaust conduit, thus taking care of the change in the demand for exhaust elastic fluid. This change in flow from extraction stage 8 is taken care of by pressure responsive device 19 actuating reducing valve 17 as already explained.

In case of heavy load on the turbine and small demand for extraction elastic fluid and/or exhaust elastic fluid, the condition may obtain where the amount of elastic fluid admittedthrough valve means 6 is more than enough to supply the demand for extraction elastic fluid and exhaust elastic fluid. Under these circumstances, since valve means 10 is regulated in terms of exhaust elastic fluid, the pressure in extraction stage 8 will tend to increase. The first effect will be to close entirely reducing valve 17. Following this, further increase in pressure in conduit 9 causes pressure responsive device 28 to open waste valve 26, thereby wasting elastic fluid from the exhaust conduit 7. This places on the turbine an artificial demand for exhaust elastic fluid, thereby causing a decrease in the pressure in the exhaust conduit 7 to effect an opening of valve means 10, bringing the pressure in extraction stage 8 to normal Value. With this arrangement, it will be seen that high pressure elastic fluid from the extraction stage is not Wasted but instead elastic fluid from exhaust conduit 7. This has the advantage of giving increased eificiency to the unit as a whole inasmuch as the elastic fluid discharged through waste valve 26 is elastic fluid which has passed entirely through the turbine and performed work therein.

When the condition obtains that the demand for exhaust elastic fluid alone is greater than the amount of elastic fluid called for by the load on the turbine, a condition which may obtain at times of light load, pressure responsive device 11 first opens wide valve means 10. If in spite of this, the supply of elastic fluid past valve means 10 is not sufficient to maintain the desired pressure in exhaust conduit 7, pressure responsive device 24 operates to open reducing valve 22, thereby admitting elastic fluid from extraction conduit 9 through conduit 21 directly to exhaust conduit '7 to supply the deficiency and maintain the pressure therein.

With the above described arrangement, it will be seen that I provide a back pressure extraction turbine with a governing means whereby the turbine is governed in terms of load and at the same time the pressure in the extraction stage and in the exhaust conduit is maintained substantially constant at the desired values.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. The combination with an elastic fluid turbine having an extraction conduit connected to an extraction stage, an exhaust conduit, and stage valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, of means responsive to the load on the turbine for regulating the admission of elastic fluid thereto, means responsive to the exhaust pressure for regulating the stage valve means, and means responsive to the pressure in the extraction stage for wasting elastic fluid from the exhaust conduit when the pressure in the extraction stage rises above a predetermined value.

2. The combination with an elastic fluid turbine having an extraction conduit connected to an extraction stage, an exhaust conduit, and stage valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, of means responsive to the load on the turbine for regulating the admission of elastic fluid thereto, means responsive to the exhaust pressure for regulating the stage valve means, a pressure reducing valve responsive to the pressure in the extraction stage for admitting elastic fluid to the extraction conduit for regulating the extraction stage pressure, and means responsive to the extraction stage pressure for wasting elastic fluid from the exhaust conduit when the pressure in the extraction stage conduit increases above a predetermined value.

3. The combination with an elastic fluid turbine having an extraction conduit connected to an extraction stage, an exhaust conduit, and stage valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, of means responsive to the load on the turbine for regulating the admission of elastic fluid thereto, means responsive to the exhaust pressure for regulating the stage valve means, a pressure reducing valve responsive to the pressure in the extraction stage for admitting elastic fluid to the extraction conduit for regulating the extraction stage pressure, another valve in the exhaust conduit, a pressure responsive device connected to the extraction conduit for opening the other valve when the pressure in the extraction conduit rises beyond a predetermined value to increase the mechanical load output of the low pressure turbine stages. 4. The combination with an elastic fluid turbine having an extraction conduit connected to an extraction stage, exhaust conduit, and stage valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, of means responsive to the load on the turbine for regulating the admission of elastic fluid thereto, means responsive to the exhaust pressure for regulating the stage valve means, a pressure reducing valve responsive to the pressure in the extraction stage for admitting elastic fluid to the extraction conduit for regulating the extraction stage pressure, means responsive to the extraction stage pressure for wasting elastic fluid from the exhaust conduit when the pressure in the extraction stage conduit increases above a predetermined value, and means responsive to the exhaust pressure for admitting elastic fluid from the extraction conduit to the exhaust conduit when the pressure in the exhaust conduit decreases below a predetermined. low value.

REGINALD G. STANDERWICK. 

